U.S. patent application number 14/617263 was filed with the patent office on 2016-03-24 for electron transport material, electrophotographic photoreceptor, process cartridge, and image forming apparatus.
The applicant listed for this patent is FUJI XEROX CO., LTD.. Invention is credited to Daisuke HARUYAMA, Masahiro IWASAKI, Yukimi KAWABATA, Jiro KORENAGA, Keisuke KUSANO, Kenta SHINGU, Yoshifumi SHOJI, Shinya YAMAMOTO.
Application Number | 20160085164 14/617263 |
Document ID | / |
Family ID | 55503844 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160085164 |
Kind Code |
A1 |
IWASAKI; Masahiro ; et
al. |
March 24, 2016 |
ELECTRON TRANSPORT MATERIAL, ELECTROPHOTOGRAPHIC PHOTORECEPTOR,
PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS
Abstract
Provided is an electron transport material represented by
formula (1): ##STR00001## wherein X represents an oxygen atom or
.dbd.C(CN).sub.2; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 each independently represent a hydrogen atom,
a halogen atom, a linear or branched alkyl group, an alkoxy group,
an aryl group, or an aralkyl group; R.sup.8, R.sup.9, and R.sup.10
each independently represent a hydrogen atom, a halogen atom, a
linear or branched alkyl group, an aralkyl group, an aryl group,
--R.sup.11--O--R.sup.12, or --R.sup.13--CO--O--R.sup.14; R.sup.11
represents a linear or branched alkylene group; R.sup.12 represents
a linear or branched alkyl group; R.sup.13 represents a single bond
or a linear or branched alkylene group; and R.sup.14 represents a
linear or branched alkyl group, an aryl group, or an aralkyl group,
provided that at least two or more groups of R.sup.8, R.sup.9, and
R.sup.10 represent a group other than a hydrogen atom.
Inventors: |
IWASAKI; Masahiro;
(Kanagawa, JP) ; YAMAMOTO; Shinya; (Kanagawa,
JP) ; KORENAGA; Jiro; (Kanagawa, JP) ;
HARUYAMA; Daisuke; (Kanagawa, JP) ; KAWABATA;
Yukimi; (Kanagawa, JP) ; KUSANO; Keisuke;
(Kanagawa, JP) ; SHINGU; Kenta; (Kanagawa, JP)
; SHOJI; Yoshifumi; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI XEROX CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
55503844 |
Appl. No.: |
14/617263 |
Filed: |
February 9, 2015 |
Current U.S.
Class: |
430/56 ; 558/406;
560/56 |
Current CPC
Class: |
C07C 69/94 20130101;
C07C 255/41 20130101; C07C 69/76 20130101; C07C 2603/18 20170501;
C07C 69/86 20130101; G03G 5/10 20130101 |
International
Class: |
G03G 15/00 20060101
G03G015/00; C07C 255/00 20060101 C07C255/00; C07C 69/76 20060101
C07C069/76 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2014 |
JP |
2014-192440 |
Claims
1. An electron transport material represented by the following
formula (1): ##STR00021## wherein in the formula (1), X represents
an oxygen atom or .dbd.C(CN).sub.2; R.sup.1, R.sup.2, R.sup.3,
R.sup.4, R.sup.5, R.sup.6, and R.sup.7 each independently represent
a hydrogen atom, a halogen atom, a linear or branched alkyl group
having 1 to 20 carbon atoms, an alkoxy group, an aryl group, or an
aralkyl group; R.sup.8, R.sup.9, and R.sup.1' each independently
represent a hydrogen atom, a halogen atom, a linear or branched
alkyl group having 1 to 20 carbon atoms, an aralkyl group, an aryl
group, --R.sup.11--O--R.sup.12, or --R.sup.13--CO--O--R.sup.14;
R.sup.11 represents a linear or branched alkylene group having 1 to
10 carbon atoms; R.sup.12 represents a linear or branched alkyl
group having 1 to 10 carbon atoms; R.sup.13 represents a single
bond or a linear or branched alkylene group having 1 to 10 carbon
atoms; and R.sup.14 represents a linear or branched alkyl group
having 1 to 10 carbon atoms, an aryl group, or an aralkyl group,
provided that at least two or more groups of R.sup.8, R.sup.9, and
R.sup.10 represent a group other than a hydrogen atom.
2. The electron transport material according to claim 1, wherein at
least one of R.sup.8, R.sup.9, and R.sup.10 represents an organic
group having 1 or more carbon atoms.
3. The electron transport material according to claim 2, wherein
the organic group is a group selected from an alkyl group, an
aralkyl group, an aryl group, --R.sup.11--O--R.sup.12 (in which
R.sup.11 is an alkylene group having 1 to 10 carbon atoms, and
R.sup.12 is an alkyl group having 1 to 10 carbon atoms), or
--R.sup.13--CO--O--R.sup.14 (in which R.sup.13 is a single bond or
an alkylene group having 1 to 10 carbon atoms, and R.sup.14 is a
linear or branched alkyl group having 1 to 10 carbon atoms or an
aralkyl group).
4. The electron transport material according to claim 1, wherein
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7
each independently represent a hydrogen atom, a halogen atom, or a
linear or branched alkyl group having 1 to 20 carbon atoms; R.sup.8
and R.sup.9 represent a linear or branched alkyl group having 1 to
10 carbon atoms or an aralkyl group and R.sup.10 represents a
hydrogen atom.
5. The electron transport material according to claim 1, wherein
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7
each independently represent a hydrogen atom, a halogen atom, or an
alkyl group having 1 to 10 carbon atoms; R.sup.8 and R.sup.9 both
represent a branched alkyl group having 3 to 10 carbon atoms or an
aralkyl group represented by --R.sup.17--Ar.sup.18 (R.sup.17
represents a branched alkylene group having 3 to 10 carbon atoms,
and Ar.sup.18 represents an unsubstituted phenyl group); and
R.sup.10 represents a hydrogen atom.
6. An electrophotographic photoreceptor comprising a conductive
substrate and a photosensitive layer including the electron
transport material according to claim 1 provided on the conductive
substrate.
7. A process cartridge comprising the electrophotographic
photoreceptor according to claim 6, that is detachable from an
image forming apparatus.
8. An image forming apparatus comprising: the electrophotographic
photoreceptor according to claim 6; a charging unit that charges
the surface of the electrophotographic photoreceptor; an
electrostatic latent image forming unit that forms an electrostatic
latent image on the surface of a charged electrophotographic
photoreceptor; a developing unit that develops the electrostatic
latent image formed on the surface of the electrophotographic
photoreceptor by a developer containing a toner to form a toner
image; and a transfer unit that transfers the toner image to the
surface of a recording medium.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
USC 119 from Japanese Patent Application No. 2014-192440 filed Sep.
22, 2014.
BACKGROUND
Technical Field
[0002] The present invention relates to an electron transport
material, an electrophotographic photoreceptor, a process
cartridge, and an image forming apparatus.
SUMMARY
[0003] According to an aspect of the invention, there is provided
an electron transport material represented by the following formula
(1):
##STR00002##
wherein in the formula (1), X represents an oxygen atom or
.dbd.C(CN).sub.2; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 each independently represent a hydrogen atom,
a halogen atom, a linear or branched alkyl group having 1 to 20
carbon atoms, an alkoxy group, an aryl group, or an aralkyl group;
R.sup.8, R.sup.9, and R.sup.10 each independently represent a
hydrogen atom, a halogen atom, a linear or branched alkyl group
having 1 to 20 carbon atoms, an aralkyl group, an aryl group,
--R.sup.1--O--R.sup.12, or --R.sup.13--CO--O--R.sup.14; R.sup.11
represents a linear or branched alkylene group having 1 to 10
carbon atoms; R.sup.12 represents a linear or branched alkyl group
having 1 to 10 carbon atoms; R.sup.13 represents a single bond or a
linear or branched alkylene group having 1 to 10 carbon atoms; and
R.sup.14 represents a linear or branched alkyl group having 1 to 10
carbon atoms, an aryl group, or an aralkyl group, provided that at
least two or more groups of R.sup.8, R.sup.9, and R.sup.10
represent a group other than a hydrogen atom.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Exemplary embodiments of the present invention will be
described in detail based on the following figures, wherein:
[0005] FIG. 1 is a schematic partial cross-sectional view showing
an electrophotographic photoreceptor according to the present
exemplary embodiment;
[0006] FIG. 2 is a schematic structural view showing an image
forming apparatus according to the present exemplary
embodiment;
[0007] FIG. 3 is another schematic structural view showing an image
forming apparatus according to the present exemplary
embodiment;
[0008] FIG. 4 is a graph showing an infrared absorption spectrum of
an exemplary compound (1-36) obtained in Synthesis Example 1;
[0009] FIG. 5 is a graph showing an infrared absorption spectrum of
an exemplary compound (1-37) obtained in Synthesis Example 2;
[0010] FIG. 6 is a graph showing an infrared absorption spectrum of
an exemplary compound (1-11) obtained in Synthesis Example 3;
[0011] FIG. 7 is a graph showing an infrared absorption spectrum of
an exemplary compound (1-12) obtained in Synthesis Example 4;
and
[0012] FIG. 8 is a graph showing an infrared absorption spectrum of
a comparative compound 1 obtained in Comparative Synthesis Example
1.
DETAILED DESCRIPTION
[0013] Hereinafter, the exemplary embodiments of the invention will
be described in detail.
[0014] Electron Transport Material
[0015] The electron transport material according to the present
exemplary embodiment is an electron transport material represented
by the following formula (1).
##STR00003##
[0016] In the formula (1), X represents an oxygen atom or
.dbd.C(CN).sub.2. R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 each independently represent a hydrogen atom,
a halogen atom, a linear or branched alkyl group having 1 to 20
carbon atoms, an alkoxy group, an aryl group, or an aralkyl group.
R.sup.8, R.sup.9, and R.sup.10 each independently represent a
hydrogen atom, a halogen atom, a linear or branched alkyl group
having 1 to 20 carbon atoms, an aralkyl group, an aryl group,
--R.sup.11--O--R.sup.12, or --R.sup.13--CO--O--R.sup.4. R.sup.11
represents a linear or branched alkylene group having 1 to 10
carbon atoms. R.sup.12 represents a linear or branched alkyl group
having 1 to 10 carbon atoms. R.sup.13 represents a single bond or a
linear or branched alkylene group having 1 to 10 carbon atoms.
R.sup.14 represents a linear or branched alkyl group having 1 to 10
carbon atoms, an aryl group, or an aralkyl group, provided that at
least two or more groups of R.sup.8, R.sup.9, and R.sup.10
represent a group other than a hydrogen atom.
[0017] As a compound having a fluorenone skeleton (hereinafter
referred to as a "fluorenone derivative" in some cases), there are
many compounds having a high electron transport capability but have
a low compatibility with a resin. Further, for example, a
fluorenone derivative having an alkoxycarbonyl group introduced
into a fluorenone skeleton as a substituent for improving the
compatibility with a resin has a higher compatibility with a resin,
as compared with the compound which does not have a substituent,
but is susceptible to an effect by a stimulus from the outside (for
example, heat, an electric field, and pressure).
[0018] Examples of the effect by a stimulus from the outside
include aggregation or diffusion of molecules of a fluorenone
derivative in a system by a stimulus such as heat and pressure from
the outside to a compound having a fluorenone derivative. Further,
in the case where the molecules of a fluorenone derivative are
easily aggregated or diffused in a system, it may be thought that
depending on a stimulus such as heat and pressure from the outside,
the distribution of fluorenone derivatives in a system is
uneven.
[0019] Meanwhile, with respect to the electron transport material
according to the present exemplary embodiment, even when a stimulus
from the outside is received, aggregation or diffusion of the
molecules over time hardly occurs in a system. The reason for this
is not clear, but it is presumed that by introducing a phenyl group
having two or more specific substituents through an ester bond, the
motion of the ester group at the 4-position in the fluorenone
skeleton is confined by steric hindrance, and thus, a change in the
molecular structure by the stimulus from the outside hardly occurs.
Specifically, for example, it may also be thought that by steric
hindrance of a substituent, a change in the physical structure of
the phenyl group such as rotation is prevented, and in addition, a
change in the chemical molecular structure such as hydrolysis of an
ester group at a high temperature and a high humidity is also
prevented.
[0020] As a result, for example, it is thought that in a resin
layer including the electron transport material according to the
present exemplary embodiment, even when a stimulus occurs from the
outside, the molecular motion of the electron transport material in
the resin layer is prevented, and thus, the morphological change of
the film hardly occurs.
[0021] Therefore, the electrophotographic photoreceptor using the
electron transport material according to the present exemplary
embodiment, even when the image formation is repeated, blurring of
an image due to a change in the film quality of the photosensitive
layer or a change of the physical properties of the photosensitive
layer surface hardly occurs. In addition, in the exemplary
embodiment, even when the image formation is repeated, the film
quality is hardly changed and the charge maintenance is good.
[0022] Furthermore, the electron transport material according to
the present exemplary embodiment has a phenyl group having two or
more substituents incorporated thereinto, and therefore, it has a
high melting point as well as high compatibility with a resin, as
compared with a case where an electron transport material has a
phenyl group having no substituent or a phenyl group having only
one substituent incorporated thereinto.
[0023] That is, by the electron transport material according to the
present exemplary embodiment, improvement of the compatibility with
a resin and prevention of the morphological change of the film as
well as an electron transport capability are accomplished. Further,
by using an electrophotographic photoreceptor in which a resin
layer including the electron transport material according to the
present exemplary embodiment is used as a photosensitive layer,
blurring of an image hardly occurs, and the charge maintenance
becomes better.
[0024] Hereinafter, the electron transport material according to
the present exemplary embodiment will be described in detail.
[0025] In the formula (1), examples of the halogen atom represented
by R.sup.1 to R.sup.7 include a fluorine atom, a chlorine atom, a
bromine atom, and an iodine atom, and from the viewpoints of the
chemical stability, a fluorine atom and a chlorine atom are
preferable.
[0026] In the formula (1), examples of the linear or branched alkyl
group having 1 to 20 carbon atoms represented by R.sup.1 to R.sup.7
include a methyl group, an ethyl group, an n-propyl group, an
n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl
group, an n-octyl group, an n-nonyl group, an n-decyl group, an
isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl
group, an isopentyl group, a neopentyl group, a tert-pentyl group,
an isohexyl group, a sec-hexyl group, a tert-hexyl group, an
isoheptyl group, a sec-heptyl group, a tert-heptyl group, an
isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl
group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a
sec-decyl group, and a tert-decyl group. In the formula (1), the
number of carbon atoms of the alkyl group represented by R.sup.1 to
R.sup.7 is preferably from 1 to 4, and more preferably from 1 to 3,
from the viewpoints of prevention of the molecular motion in a
layer and compatibility.
[0027] In the formula (1), examples of the alkoxy group represented
by R.sup.1 to R.sup.7 include a linear or branched alkoxy group
having 1 to 4 carbon atoms, and specific examples thereof include a
methoxy group, an ethoxy group, a propoxy group, and a butoxy
group. In the formula (1), the number of carbon atoms of the alkoxy
group represented by R.sup.1 to R.sup.7 is preferably from 1 to 3,
from the viewpoints of prevention of the morphological change of
the film.
[0028] In the formula (1), the aryl group represented by R.sup.1 to
R.sup.7 may or may not have a substituent, and examples thereof
include substituted or unsubstituted phenyl groups. Examples of the
substituent contained in the aryl group include an alkyl group
having 1 to 10 carbon atoms, an alkoxy group, and a halogen atom.
Specific examples of the aryl group include a phenyl group, a
methylphenyl group (tolyl group), a dimethylphenyl group, and an
ethylphenyl group.
[0029] In the formula (1), examples of the aralkyl group
represented by R.sup.1 to R.sup.7 include a group represented by
--R.sup.15--Ar.sup.16, provided that R.sup.15 represents an
alkylene group and Ar.sup.16 represents a substituted or
unsubstituted aryl group.
[0030] Examples of the alkylene group represented by R.sup.15
include a linear or branched alkylene group having 1 to 12 carbon
atoms, and specific examples thereof include a methylene group, an
ethylene group, an n-propylene group, an isopropylene group, an
n-butylene group, an isobutylene group, a sec-butylene group, a
tert-butylene group, an n-pentylene group, an isopentylene group, a
neopentylene group, and a tert-pentylene group. The number of
carbon atoms of the alkylene group represented by R.sup.15 is
preferably from 1 to 10, and more preferably from 1 to 6, from the
viewpoints of compatibility and solubility.
[0031] Examples of the substituted or unsubstituted aryl group
represented by Ar.sup.16 include the same groups as set forth above
with respect to the aryl group represented by R.sup.1 to R.sup.7 in
the formula (1), and examples of the substituent that the aryl
group has also include the same groups as set forth above.
[0032] In the formula (1), specific examples of the aralkyl group
represented by R.sup.1 to R.sup.7 include a benzyl group, a
methylbenzyl group, a dimethylbenzyl group, a phenylethyl group, a
methylphenylethyl group, a phenylpropyl group, and a phenylbutyl
group.
[0033] R.sup.1 to R.sup.7 in the formula (1) are each independently
preferably a hydrogen atom, a halogen atom, a linear alkyl group
having 1 to 10 carbon atoms, or a linear alkoxy group having 1 to
10 carbon atoms, and more preferably a hydrogen atom, from the
viewpoints of a high electron transport capability and prevention
of the morphological change of the film.
[0034] Furthermore, examples of a combination of R.sup.1 to R.sup.7
in the formula (1) include a combination in which R.sup.1 to
R.sup.7 are all hydrogen atoms, a combination in which six groups
out of R.sup.1 to R.sup.7 are hydrogen atoms and the one group is a
group other than a hydrogen atom, and a combination in which five
groups out of R.sup.1 to R.sup.7 are hydrogen atoms and the two
groups are groups other than a hydrogen atom.
[0035] In the formula (1), examples of the halogen atom represented
by R.sup.8 to R.sup.10 include a fluorine atom, a chlorine atom, a
bromine atom, and an iodine atom, and from the viewpoints of the
chemical stability, a fluorine atom and a chlorine atom are
preferable.
[0036] In the formula (1), examples of the linear alkyl group with
respect to the linear or branched alkyl group having 1 to 20 carbon
atoms represented by R.sup.8 to R.sup.10 include a methyl group, an
ethyl group, an n-propyl group, an n-butyl group, an n-pentyl
group, an n-hexyl group, an n-heptyl group, an n-octyl group, an
n-nonyl group, and an n-decyl group.
[0037] In the formula (1), examples of the branched alkyl group
with respect to the linear or branched alkyl group having 1 to 20
carbon atoms represented by R.sup.8 to R.sup.10 include an
isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl
group, an isopentyl group, a neopentyl group, a tert-pentyl group,
an isohexyl group, a sec-hexyl group, a tert-hexyl group, an
isoheptyl group, a sec-heptyl group, a tert-heptyl group, an
isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl
group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a
sec-decyl group, and a tert-decyl group.
[0038] In the formula (1), the number of carbon atoms of the linear
alkyl group represented by R.sup.8 to R.sup.10 is preferably from 1
to 10, and more preferably from 1 to 6, from the viewpoints of
improvement of compatibility with a resin and prevention of film
morphology. Further, in the formula (1), the number of carbon atoms
of the branched alkyl group represented by R.sup.8 to R.sup.10 is
preferably from 3 to 10, and more preferably from 3 to 6, from the
viewpoints of improvement of the compatibility with a resin.
[0039] In the formula (1), examples of the aralkyl group
represented by R.sup.8 to R.sup.10 include a group represented by
--R.sup.17--Ar.sup.18, provided that R.sup.17 represents an
alkylene group and Ar.sup.18 represents a substituted or
unsubstituted aryl group.
[0040] Examples of the alkylene group represented by R.sup.17
include the same groups as set forth above with respect to R.sup.15
of the group represented by --R.sup.15--Ar.sup.16. The number of
carbon atoms of the alkylene group represented by R.sup.17 is
preferably from 1 to 10, and preferably from 1 to 6, from the
viewpoints of prevention of the morphological change of the
film.
[0041] Examples of the aryl group represented by Ar.sup.18 include
the same groups as set forth above with respect to Ar.sup.16 of the
group represented by --R.sup.15--Ar.sup.16.
[0042] In the formula (1), specific examples of the aralkyl group
represented by R.sup.8 to R.sup.10 include the specific examples of
the aralkyl group represented by R.sup.1 to R.sup.7.
[0043] In the formula (1), specific examples of the aryl group
represented by R.sup.8 to R.sup.10 include the specific examples of
the aryl group represented by R.sup.1 to R.sup.7.
[0044] In the formula (1), in a group represented by
--R.sup.11--O--R.sup.12 represented by R.sup.8 to R.sup.10,
R.sup.11 represents a linear or branched alkylene group having 1 to
10 carbon atoms, and R.sup.12 represents a linear or branched alkyl
group having 1 to 10 carbon atoms.
[0045] Examples of the linear or branched alkylene group having 1
to 10 carbon atoms represented by R.sup.11 include the same groups
as set forth above with respect to the specific examples of the
alkylene group represented by R.sup.15 in the group represented by
--R.sup.15--Ar.sup.16. The number of carbon atoms of the alkylene
group represented by R.sup.11 is preferably from 1 to 10. Further,
the alkylene group represented by R.sup.11 is preferably a branched
alkylene group having 1 to 10 carbon atoms.
[0046] Examples of the linear or branched alkyl group having 1 to
10 carbon atoms represented by R.sup.12 include the same groups as
set forth above with respect to the specific examples of the alkyl
group represented by R.sup.8 to R.sup.10. The number of carbon
atoms of the alkyl group represented by R.sup.12 is preferably from
1 to 10.
[0047] As the group represented by R.sup.11--O--R.sup.12, which is
represented by R.sup.8 to R.sup.10, above all, a methoxymethyl
group, an ethoxymethyl group, or a phenoxymethyl group is
preferable.
[0048] In the formula (1), in the group represented by
--R.sup.13--CO--O--R.sup.14, which is represented by R.sup.8 to
R.sup.10, R.sup.13 represents a single bond or a linear or branched
alkylene group having 1 to 10 carbon atoms, and R.sup.14 represents
a linear or branched alkyl group having 1 to 10 carbon atoms, an
aryl group, or an aralkyl group.
[0049] Examples of the linear or branched alkylene group having 1
to 10 carbon atoms represented by R.sup.13 include the same groups
as set forth above with respect to the specific examples of the
alkylene group represented by R.sup.15 of the group represented by
--R.sup.15--Ar.sup.16. The number of carbon atoms of the alkylene
group represented by R.sup.13 is preferably from 1 to 10. Further,
the alkylene group represented by R.sup.13 is preferably a branched
alkylene group having 1 to 6 carbon atoms.
[0050] Examples of the linear or branched alkyl group having 1 to
10 carbon atoms represented by R.sup.14 include the same groups as
set forth above with respect to the specific examples of the alkyl
group represented by R.sup.8 to R.sup.10. The number of carbon
atoms of the alkyl group represented by R.sup.14 is preferably from
1 to 10. Further, the alkyl group represented by R.sup.14 is
preferably a branched alkyl group having 1 to 10 carbon atoms.
[0051] Examples of the aryl group represented by R.sup.14 include
the same groups as set forth above with respect to the specific
examples of the aryl group represented by Ar.sup.16 of the group
represented by --R.sup.15--Ar.sup.16. The substituents introduced
to the aryl group, the preferable groups, and the like are the same
as for the aryl group represented by Ar.sup.16 of the group
represented by --R.sup.5--Ar.sup.6.
[0052] Examples of the aralkyl group represented by R.sup.14
include the same groups as set forth above with respect to the
specific examples of the aralkyl group represented by R.sup.8 to
R.sup.10. The preferable groups are the same as for the aralkyl
group represented by R.sup.8 to R.sup.10.
[0053] As the group represented by --R.sup.13--CO--O--R.sup.14,
which is represented by R.sup.8 to R.sup.10, above all, a
methoxycarbonylmethyl and an ethoxycarbonylmethyl group are
preferable.
[0054] The binding position of R.sup.10 in the formula (1) may be
any of the 3-position, the 5-position, and the 6-position as long
as it is a position other than the 2-position to which R.sup.8 is
bonded and the 4-position to which R.sup.9 is bonded, and the
6-position is more preferable.
[0055] Above all, R.sup.8 to R.sup.10 in the formula (1) are each
independently preferably a hydrogen atom, a chlorine atom, a linear
alkyl group having 1 to 10 carbon atoms, a branched alkyl group
having 3 to 10 carbon atoms, the aralkyl group represented by
--R.sup.17--Ar.sup.18 (R.sup.17 represents a branched alkylene
group having 3 to 10 carbon atoms and Ar.sup.18 represents a
substituted or unsubstituted phenyl group), --R.sup.11--O--R.sup.12
(R.sup.11 represents an alkylene group having 1 to 10 carbon atoms,
and R.sup.12 represents an alkyl group having 1 to 10 carbon
atoms), --R.sup.13--CO--O--R.sup.14 (R.sup.13 represents a single
bond or an alkylene group having 1 to 10 carbon atoms, and R.sup.14
represents a linear or branched alkyl group having 1 to 10 carbon
atoms or an aralkyl group); and more preferably a hydrogen atom, a
linear alkyl group having 1 to 10 carbon atoms, or a branched alkyl
group having 3 to 10 carbon atoms.
[0056] R.sup.8 to R.sup.10 in the formula (1) may be any groups
such that two or more groups of these groups are groups other than
a hydrogen atom, but it is preferable that one or more groups of
R.sup.8 to R.sup.10 is each an organic group having 1 or more
carbon atoms (that is, an alkyl group, an aralkyl group, an aryl
group, --R.sup.1--O--R.sup.12, or --R.sup.13--CO--O--R.sup.4), and
it is more preferable that two or more groups of R.sup.8 to
R.sup.10 is each an organic group having 1 or more carbon
atoms.
[0057] Furthermore, it is preferable that R.sup.8 and R.sup.9 in
the formula (1) are groups other than a hydrogen atom (R.sup.10 is
a hydrogen atom or a group other than a hydrogen atom), and it is
more preferable that R.sup.10 is a hydrogen atom, and R.sup.8 and
R.sup.9 are a group other than a hydrogen atom.
[0058] The electron transport material represented by the formula
(1) is preferably the electron transport material, in which R.sup.1
to R.sup.7 each independently represent a hydrogen atom, a halogen
atom, or an alkyl group, R.sup.8 and R.sup.9 represent a linear or
branched alkyl group having 1 to 10 carbon atoms, or an aralkyl
group, and R.sup.10 is a hydrogen atom; in particular, in which
R.sup.1 to R.sup.7 each independently represent a hydrogen atom, a
halogen atom, or an alkyl group having 1 to 10 carbon atoms,
further, R.sup.8 and R.sup.9 are both a branched alkyl group having
3 to 10 carbon atoms or an aralkyl group represented by
--R.sup.7--Ar.sup.8 (R.sup.17 is a branched alkylene group having 3
to 10 carbon atoms and Ar.sup.18 is an unsubstituted phenyl group),
and R.sup.10 represents a hydrogen atom, from the viewpoints of
improvement of compatibility with a resin and prevention of film
morphology.
[0059] Hereinafter, the exemplary compounds of the electron
transport material represented by the formula (1) are shown, but
the invention is not limited thereto.
[0060] Furthermore, the "o-position" as the "position of R.sup.10"
in the Tables below denotes that R.sup.10 binds at the 6-position
of a benzene ring, and the "m-position" as the "position of
R.sup.10" denotes that R.sup.10 binds at the 5-position of a
benzene ring.
TABLE-US-00001 Exemplary Compound X R.sup.1 R.sup.2 R.sup.3 R.sup.4
R.sup.5 R.sup.6 R.sup.7 R.sup.8 1-1 .dbd.C(CN).sub.2 --H --H --H
--H --H --H --H --CH.sub.3 1-2 .dbd.C(CN).sub.2 --H --H --H --H --H
--H --H --CH.sub.3 1-3 .dbd.C(CN).sub.2 --H --H --H --H --H --H --H
--CH.sub.3 1-4 .dbd.C(CN).sub.2 --H --H --H --H --H --H --H
--CH.sub.3 1-5 .dbd.C(CN).sub.2 --H --H --H --H --H --H --H
--CH.sub.2OCH.sub.3 1-6 .dbd.C(CN).sub.2 --H --H --H --H --H --H
--H --CH(CH.sub.3).sub.2 1-7 .dbd.C(CN).sub.2 --H --H --H --H --H
--H --H --CH(CH.sub.3).sub.2 1-8 .dbd.C(CN).sub.2 --H --H --H --H
--H --H --H --CH.sub.3 1-9 .dbd.C(CN).sub.2 --H --H --H --H --H --H
--H -t-C.sub.4H.sub.9 1-10 .dbd.C(CN).sub.2 --H --H --H --H --H --H
--H -t-C.sub.4H.sub.9 1-11 .dbd.C(CN).sub.2 --H --H --H --H --H --H
--H --C(CH.sub.3).sub.2CH.sub.2CH.sub.3 1-12 .dbd.C(CN).sub.2 --H
--H --H --H --H --H --H ##STR00004## 1-13 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-14 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-15 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-16 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-17 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-18 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-19 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-20 .dbd.C(CN).sub.2 --H --H
--H --H --H --H --H -t-C.sub.4H.sub.9 1-21 .dbd.C(CN).sub.2 --H Cl
--H --H Cl --H --H --C(CH.sub.3).sub.2CH.sub.2CH.sub.3 1-22
.dbd.C(CN).sub.2 --H Cl --H --H Cl --H --H -n-C.sub.4H.sub.9 1-23
.dbd.C(CN).sub.2 --H --CH.sub.3 --H --H --H --H --H --Cl 1-24
.dbd.C(CN).sub.2 --H --OCH.sub.3 --H --H --H --H --H
-n-C.sub.9H.sub.19 1-25 .dbd.C(CN).sub.2 --OCH.sub.3 --H --H --H
--H --H --H --CH.sub.2OCH.sub.3 1-26 .dbd.O --H --H --H --H --H --H
--H --CH.sub.3 1-27 .dbd.O --H --H --H --H --H --H --H --CH.sub.3
1-28 .dbd.O --H --H --H --H --H --H --H --CH.sub.3 1-29 .dbd.O --H
--H --H --H --H --H --H --CH.sub.3 1-30 .dbd.O --H --H --H --H --H
--H --H --CH.sub.2OCH.sub.3 1-31 .dbd.O --H --H --H --H --H --H --H
--CH(CH.sub.3).sub.2 1-32 .dbd.O --H --H --H --H --H --H --H
--CH(CH.sub.3).sub.2 1-33 .dbd.O --H --H --H --H --H --H --H
--CH.sub.3 1-34 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-35 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-36 .dbd.O --H --H --H --H --H --H --H
--C(CH.sub.3).sub.2CH.sub.2CH.sub.3 1-37 .dbd.O --H --H --H --H --H
--H --H ##STR00005## 1-38 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-39 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-40 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-41 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-42 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-43 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-44 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-45 .dbd.O --H --H --H --H --H --H --H
-t-C.sub.4H.sub.9 1-46 .dbd.O --H Cl --H --H Cl --H --H
--C(CH.sub.3).sub.2CH.sub.2CH.sub.3 1-47 .dbd.O --H Cl --H --H Cl
--H --H -n-C.sub.4H.sub.9 1-48 .dbd.O --H --CH.sub.3 --H --H --H
--H --H --Cl 1-49 .dbd.O --H --OCH.sub.3 --H --H --H --H --H
-n-C.sub.9H.sub.19 1-50 .dbd.O --OCH.sub.3 --H --H --H --H --H --H
--CH.sub.2OCH.sub.3 Exemplary position of Compound R.sup.9 R.sup.10
R.sup.10 1-1 --CH.sub.3 -- --H 1-2 --CH.sub.3 o-position --CH.sub.3
1-3 --CH.sub.3 m-position --CH.sub.3 1-4 --C.sub.2H.sub.5 -- --H
1-5 -t-C.sub.4H.sub.9 o-position --CH.sub.2OCH.sub.3 1-6 --CH.sub.3
o-position --CH(CH.sub.3).sub.2 1-7 -t-C.sub.4H.sub.9 o-position
--CH(CH.sub.3).sub.2 1-8 -n-C.sub.6H.sub.13 -- --H 1-9
--C.sub.2H.sub.5 o-position -t-C.sub.4H.sub.9 1-10
-t-C.sub.4H.sub.9 -- --H 1-11 --C(CH.sub.3).sub.2CH.sub.2CH.sub.3
-- --H 1-12 ##STR00006## -- --H 1-13
--CH.sub.2CH.sub.2CO.sub.2CH.sub.3 o-position -t-C.sub.4H.sub.9
1-14 --CH.sub.2CH.sub.2CO.sub.2CH.sub.2CH.sub.3 o-position
-t-C.sub.4H.sub.9 1-15
--CH.sub.2CH.sub.2CO.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.3
o-position -t-C.sub.4H.sub.9 1-16
--CH.sub.2CH.sub.2CO.sub.2-nC.sub.6H.sub.13 o-position
-t-C.sub.4H.sub.9 1-17 --CH.sub.2CH.sub.2CO.sub.2-nC.sub.8H.sub.17
o-position -t-C.sub.4H.sub.9 1-18
--CH.sub.2CH.sub.2CO.sub.2-isoC.sub.8H.sub.17 o-position
-t-C.sub.4H.sub.9 1-19 ##STR00007## o-position -t-C.sub.4H.sub.9
1-20 --CO.sub.2-isoC.sub.8H.sub.17 o-position -t-C.sub.4H.sub.9
1-21 --C(CH.sub.3).sub.2CH.sub.2CH.sub.3 -- --H 1-22
-n-C.sub.4H.sub.9 -- --H 1-23 --CO.sub.2-isoC.sub.8H.sub.17 -- --H
1-24 --CO.sub.2-isoC.sub.8H.sub.17 -- --H 1-25
--CO.sub.2-isoC.sub.8H.sub.17 -- --H 1-26 --CH.sub.3 -- --H 1-27
--CH.sub.3 o-position --CH.sub.3 1-28 --CH.sub.3 m-position
--CH.sub.3 1-29 --C.sub.2H.sub.5 -- --H 1-30 -t-C.sub.4H.sub.9
o-position --CH.sub.2OCH.sub.3 1-31 --CH.sub.3 o-position
--CH(CH.sub.3).sub.2 1-32 -t-C.sub.4H.sub.9 o-position
--CH(CH.sub.3).sub.2 1-33 -n-C.sub.6H.sub.13 -- --H 1-34
--C.sub.2H.sub.5 o-position -t-C.sub.4H.sub.9 1-35
-t-C.sub.4H.sub.9 -- --H 1-36 --C(CH.sub.3).sub.2CH.sub.2CH.sub.3
-- --H 1-37 ##STR00008## -- --H 1-38
--CH.sub.2CH.sub.2CO.sub.2CH.sub.3 o-position -t-C.sub.4H.sub.9
1-39 --CH.sub.2CH.sub.2CO.sub.2CH.sub.2CH.sub.3 o-position
-t-C.sub.4H.sub.9 1-40
--CH.sub.2CH.sub.2CO.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.3
o-position -t-C.sub.4H.sub.9 1-41
--CH.sub.2CH.sub.2CO.sub.2-nC.sub.6H.sub.13 o-position
-t-C.sub.4H.sub.9 1-42 --CH.sub.2CH.sub.2CO.sub.2-nC.sub.8H.sub.17
o-position -t-C.sub.4H.sub.9 1-43
--CH.sub.2CH.sub.2CO.sub.2-isoC.sub.8H.sub.17 o-position
-t-C.sub.4H.sub.9 1-44 ##STR00009## o-position -t-C.sub.4H.sub.9
1-45 --CO.sub.2-isoC.sub.8H.sub.17 o-position -t-C.sub.4H.sub.9
1-46 --C(CH.sub.3).sub.2CH.sub.2CH.sub.3 -- --H 1-47
-n-C.sub.4H.sub.9 -- --H 1-48 --CO.sub.2-isoC.sub.8H.sub.17 -- --H
1-49 --CO.sub.2-isoC.sub.8H.sub.17 -- --H 1-50
--CO.sub.2-isoC.sub.8H.sub.17 -- --H
[0061] Exemplary compound, Position of R.sup.10, o-Position,
m-Position, o-Position, o-Position, o-Position, o-Position,
o-Position, o-Position, o-Position, o-Position, o-Position,
o-Position, o-Position, o-Position
[0062] Hereinbelow, a method for preparing the electron transport
material according to the present exemplary embodiment will be
described.
[0063] The electron transport material represented by the formula
(1) is synthesized by a known method.
[0064] By way of an example, a method for synthesizing a compound
in which X is an oxygen atom or .dbd.C(CN).sub.2, R.sup.1 to
R.sup.7 are all hydrogen atoms, R.sup.8 and R.sup.9 are each a
methyl group, and R.sup.10 is a hydrogen atom in the electron
transport material represented by the formula (1) will be described
below, but the invention is not limited thereto.
[0065] The compound in which X is an oxygen atom in the electron
transport material represented by the formula (1) is obtained, for
example, through the reactions of the following routes (1) and (2).
Further, the compound in which X is .dbd.C(CN).sub.2 in the
electron transport material represented by the formula (1) is
obtained, for example, through reactions of the following routes
(1) to (3).
[0066] Route 1): 9-Fluorenone-4-carboxylic acid is reacted with
thionyl chloride to afford an acid chloride.
[0067] Route 2): By reacting the obtained acid chloride with a
phenol derivative (for example, 2,4-xylenol) in the presence of a
base catalyst (for example, pyridine, piperidine, and
triethylamine) to obtain the compound of the formula (1) in which X
is an oxygen atom.
[0068] Route 3) By adding malonitrile to the compound of the
formula (1) in which X is an oxygen atom and reacting them with
each other in the presence of the same base catalyst as in the
route 2) to obtain the compound of the formula (1) in which X is a
dicyanomethylene group (.dbd.C(CN).sub.2).
##STR00010##
[0069] The electron transport material according to the present
exemplary embodiment has a high electron transport capability and a
high compatibility with a resin, and hardly causes aggregation or
diffusion of the molecules in a system, and therefore, it hardly
causes a morphological change in a layer. The electron transport
material according to the present exemplary embodiment is suitable
for, for example, a photosensitive layer of an electrophotographic
photoreceptor (in particular, a single layer type photoreceptor) as
described later.
[0070] Electrophotographic Photoreceptor
[0071] The electrophotographic photoreceptor according to the
present exemplary embodiment has a conductive substrate and a
photosensitive layer provided on the conductive substrate, in which
the photosensitive layer includes an electron transport material
represented by the formula (1) (hereinafter referred to as a
"specific electron transport material" in some cases).
[0072] Here, the photosensitive layer may be a function integration
type photosensitive layer (single layer type photosensitive layer)
having both a charge transport capability and a charge generating
capability, and may be a function separation type photosensitive
layer including a charge transport layer and a charge generating
layer. Further, in the function separation type photosensitive
layer, the specific electron transport material is included in the
charge transport layer.
[0073] Hereinafter, as an example, a positively charged organic
photoreceptor (hereinafter simply referred to as a "photoreceptor"
or a "single layer type photoreceptor" in some cases) having a
single layer type photosensitive layer on a conductive substrate
will be described in detail with reference to the drawings.
[0074] FIG. 1 schematically shows a cross-sectional view of a part
of the electrophotographic photoreceptor 10 according to the
present exemplary embodiment.
[0075] The electrophotographic photoreceptor 10 shown in FIG. 1
includes a conductive substrate 3, and has a structure in which an
undercoat layer 1 and a single layer type photosensitive layer 2
are provided in this order on the conductive substrate 3.
[0076] Further, the undercoat layer 1 is a layer which is provided,
as desired. That is, the single layer type photosensitive layer 2
may be provided directly or through the undercoat layer 1 on the
conductive substrate 3.
[0077] Further, other layers may be provided, as necessary.
Specifically, for example, a protective layer may be provided on a
single layer type photosensitive layer 2, as desired.
[0078] Hereinafter, each of the layers of the electrophotographic
photoreceptor according to the present exemplary embodiment will be
described in detail. Further, the explanations of the symbols are
omitted.
[0079] Conductive Substrate
[0080] Examples of the conductive substrate include metal plates,
metal drums, and metal belts containing a metal (such as aluminum,
copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold,
and platinum), and alloys thereof (such as stainless steel).
Further, other examples of the conductive substrate include papers,
resin films, and belts which are coated, deposited, or laminated
with a conductive compound (such as a conductive polymer and indium
oxide), a metal (such as aluminum, palladium, and gold), or alloys
thereof. The term "conductive" means that the volume resistivity is
less than 10.sup.13 .OMEGA.cm.
[0081] When the electrophotographic photoreceptor is used in a
laser printer, the surface of the conductive substrate is
preferably roughened so as to have a centerline average roughness
(Ra) of 0.04 .mu.m to 0.5 .mu.m sequentially to prevent
interference fringes which are formed when irradiated with laser
light. Further, when an incoherent light is used as a light source,
surface roughening for preventing interference fringes is not
particularly necessary, but occurrence of defects due to the
irregularities on the surface of the conductive substrate is
prevented, which is thus suitable for achieving a longer service
life.
[0082] Examples of the method for surface roughening include wet
honing in which an abrasive suspended in water is blown onto a
support, centerless grinding in which a support is continuously
ground by pressing a conductive substrate onto a rotating grind
stone, and anodic oxidation treatment.
[0083] Other examples of the method for surface roughening include
a method for surface roughening by forming a layer of a resin in
which conductive or semiconductive particles are dispersed in the
resin so that the surface roughening is achieved by forming a layer
on the surface of a conductive substrate, while not roughening the
surface of the conductive substrate.
[0084] In the surface roughening treatment by anodic oxidation, an
oxide film is formed on the surface of a conductive substrate by
anodic oxidation in which a metal (for example, aluminum)
conductive substrate as an anode is anodized in an electrolyte
solution. Examples of the electrolyte solution include a sulfuric
acid solution and an oxalic acid solution. However, the porous
anodic oxide film formed by anodic oxidation as it is chemically
active, easily contaminated and has a large resistance variation
depending on the environment. Therefore, it is preferable to
conduct a sealing treatment in which for a porous anodic oxide
film, fine pores of the oxide film are sealed by cubical expansion
caused by a hydration in pressurized water vapor or boiled water
(to which a metallic salt such as a nickel salt may be added) to
transform the anodic oxide into a more stable hydrated oxide.
[0085] The film thickness of the anodic oxide film is preferably
from 0.3 .mu.m to 15 .mu.m. When the thickness of the anodic oxide
film is within the above range, a barrier property against
injection tends to be exerted and an increase in the residual
potential due to the repeated use tends to be prevented.
[0086] The conductive substrate may be subjected to a treatment
with an acidic aqueous solution or a boehmite treatment.
[0087] The treatment with an acidic treatment solution is carried
out as follows. First, an acidic treatment solution including
phosphoric acid, chromic acid, and hydrofluoric acid is prepared.
The mixing ratio of phosphoric acid, chromic acid, and hydrofluoric
acid in the acidic treatment solution is, for example, a ratio such
that from 10% by weight to 11% by weight of phosphoric acid, from
3% by weight to 5% by weight of chromic acid, and from 0.5% by
weight to 2% by weight of hydrofluoric acid. The concentration of
the total acid components is preferably in the range of 13.5% by
weight to 18% by weight. The treatment temperature is, for example,
preferably from 42.degree. C. to 48.degree. C. The film thickness
of the film is preferably from 0.3 .mu.m to 15 .mu.m.
[0088] The boehmite treatment is carried out by immersing the
substrate in pure water at a temperature of 90.degree. C. to
100.degree. C. for 5 minutes to 60 minutes, or by bringing it into
contact with heated water vapor at a temperature of 90.degree. C.
to 120.degree. C. for 5 minutes to 60 minutes. The film thickness
of the film is preferably from 0.1 .mu.m to 5 .mu.m. The film may
further be subjected to an anodic oxidation treatment using an
electrolyte solution which sparingly dissolves the film, such as
adipic acid, boric acid, borate, phosphate, phthalate, maleate,
benzoate, tartrate, and citrate solutions.
[0089] Undercoat Layer
[0090] The undercoat layer is, for example, a layer including
inorganic particles and a binder resin.
[0091] Examples of the inorganic particles include inorganic
particles having powder resistance (volume resistivity) of about
10.sup.2 .OMEGA.cm to 10.sup.11 .OMEGA.cm.
[0092] Among these, as the inorganic particles having the
resistance values above, metal oxide particles such as tin oxide
particles, titanium oxide particles, zinc oxide particles, and
zirconium oxide particles are preferable, and zinc oxide particles
are more preferable.
[0093] The specific surface area of the inorganic particles as
measured by a BET method is, for example, preferably 10 m.sup.2/g
or more.
[0094] The volume average particle diameter of the inorganic
particles is, for example, preferably from 50 nm to 2000 nm
(preferably from 60 nm to 1000 nm).
[0095] The content of the inorganic particles is, for example,
preferably from 10% by weight to 80% by weight, and more preferably
from 40% by weight to 80% by weight, based on the binder resin.
[0096] The inorganic particles may be the ones which have been
subjected to a surface treatment. The inorganic particles which
have been subjected to different surface treatments or have
different particle diameters may be used in combination of two or
more kinds.
[0097] Examples of the surface treatment agent include a silane
coupling agent, a titanate coupling agent, an aluminum coupling
agent, and a surfactant. Particularly, the silane coupling agent is
preferable, and a silane coupling agent having an amino group is
more preferable.
[0098] Examples of the silane coupling agent having an amino group
include 3-aminopropyltriethoxysilane,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and
N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, but are not
limited thereto.
[0099] These silane coupling agents may be used as a mixture of two
or more kinds thereof. For example, a silane coupling agent having
an amino group and the other silane coupling agent may be used in
combination. Examples of the other silane coupling agent include
vinyltrimethoxysilane,
3-methacryloxypropyl-tris(2-methoxyethoxy)silane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane,
3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane,
N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and
3-chloropropyltrimethoxysilane, but are not limited thereto.
[0100] The surface treatment method using a surface treatment agent
may be any one of known methods, and may be either a dry method or
a wet method.
[0101] The amount of the surface treatment agent for treatment is,
for example, preferably from 0.5% by weight to 10% by weight, based
on the inorganic particles.
[0102] Here, inorganic particles and an electron acceptive compound
(acceptor compound) are preferably included in the undercoat layer
from the viewpoint of superior long-term stability of electrical
characteristics and carrier blocking property.
[0103] Examples of the electron acceptive compound include electron
transport materials such as quinone compounds such as chloranil and
bromanil; tetracyanoquinodimethane compounds; fluorenone compounds
such as 2,4,7-trinitrofluorenone and
2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as
2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole,
2,5-bis(4-naphthyl)-1,3,4-oxadiazole, and
2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds;
thiophene compounds; and diphenoquinone compounds such as
3,3',5,5'-tetra-t-butyldiphenoquinone.
[0104] Particularly, as the electron acceptive compound, compounds
having an anthraquinone structure are preferable. As the electron
acceptive compounds having an anthraquinone structure,
hydroxyanthraquinone compounds, aminoanthraquinone compounds,
aminohydroxyanthraquinone compounds, and the like are preferable,
and specifically, anthraquinone, alizarin, quinizarin, anthrarufin,
purpurin, and the like are preferable.
[0105] The electron acceptive compound may be included as dispersed
with the inorganic particles in the undercoat layer, or may be
included as attached to the surface of the inorganic particles.
[0106] Examples of the method of attaching the electron acceptive
compound to the surface of the inorganic particles include a dry
method and a wet method.
[0107] The dry method is a method for attaching an electron
acceptive compound to the surface of the inorganic particles, in
which the electron acceptive compound is added dropwise to the
inorganic particles or sprayed thereto together with dry air or
nitrogen gas, either directly or in the form of a solution in which
the electron acceptive compound is dissolved in an organic solvent,
while the inorganic particles are stirred with a mixer or the like
having a high shearing force. The addition or spraying of the
electron acceptive compound is preferably carried out at a
temperature not higher than the boiling point of the solvent. After
the addition or spraying of the electron acceptive compound, the
inorganic particles may further be subjected to baking at a
temperature of 100.degree. C. or higher. The baking may be carried
out at any temperature and time without limitation, by which
desired electrophotographic characteristics may be obtained.
[0108] The wet method is a method for attaching an electron
acceptive compound to the surface of the inorganic particles, in
which the inorganic particles are dispersed in a solvent by means
of stirring, ultrasonic wave, a sand mill, an attritor, a ball
mill, or the like, then the electron acceptive compound is added
and the mixture is further stirred or dispersed, and thereafter,
the solvent is removed. As a method for removing the solvent, the
solvent is removed by filtration or distillation. After removing
the solvent, the particles may further be subjected to baking at a
temperature of 100.degree. C. or higher. The baking may be carried
out at any temperature and time without limitation, in which
desired electrophotographic characteristics may be obtained. In the
wet method, the moisture contained in the inorganic particles may
be removed prior to the addition of an electron acceptive compound,
and examples of a method for removing the moisture include a method
for removing the moisture by stirring and heating the inorganic
particles in a solvent or by azeotropic removal with the
solvent.
[0109] Furthermore, the attachment of the electron acceptive
compound may be carried out before or after the inorganic particles
are subjected to a surface treatment using a surface treatment
agent, and the attachment of the electron acceptive compound may be
carried out at the same time with the surface treatment using a
surface treatment agent.
[0110] The content of the electron acceptive compound is, for
example, preferably from 0.01% by weight to 20% by weight, and more
preferably from 0.01% by weight to 10% by weight, based on the
inorganic particles.
[0111] Examples of the binder resin used in the undercoat layer
include known materials, such as well-known polymeric compounds
such as acetal resins (for example, polyvinylbutyral), polyvinyl
alcohol resins, polyvinyl acetal resins, casein resins, polyamide
resins, cellulose resins, gelatins, polyurethane resins, polyester
resins, unsaturated polyether resins, methacrylic resins, acrylic
resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl
chloride-vinyl acetate-maleic anhydride resins, silicone resins,
silicone-alkyd resins, urea resins, phenol resins,
phenol-formaldehyde resins, melamine resins, urethane resins, alkyd
resins, and epoxy resins; zirconium chelate compounds; titanium
chelate compounds; aluminum chelate compounds; titaniumalkoxide
compounds; organic titanium compounds; and silane coupling
agents.
[0112] Other examples of the binder resin used in the undercoat
layer include charge transport resins having charge transport
groups, and conductive resins (for example, polyaniline).
[0113] Among these, as the binder resin used in the undercoat
layer, a resin which is insoluble in a coating solvent of an upper
layer is suitable, and particularly, thermosetting resins such as
urea resins, phenol resins, phenol-formaldehyde resins, melamine
resins, urethane resins, unsaturated polyester resins, alkyd
resins, and epoxy resins; and resins obtained by a reaction of a
curing agent and at least one kind of resin selected from the group
consisting of polyamide resins, polyester resins, polyether resins,
methacrylic resins, acrylic resins, polyvinyl alcohol resins, and
polyvinyl acetal resins are suitable.
[0114] In the case where these binder resins are used in
combination of two or more kinds thereof, the mixing ratio is set
as appropriate.
[0115] Various additives may be used for the undercoat layer to
improve electrical characteristics, environmental stability, or
image quality.
[0116] Examples of the additives include known materials such as
the polycyclic condensed type or azo type of the electron transport
pigments, zirconium chelate compounds, titanium chelate compounds,
aluminum chelate compounds, titanium alkoxide compounds, organic
titanium compounds, and silane coupling agents. A silane coupling
agent, which is used for surface treatment of inorganic particles
as described above, may also be added to the undercoat layer as an
additive.
[0117] Examples of the silane coupling agent as an additive include
vinyltrimethoxysilane,
3-methacryloxypropyl-tris(2-methoxyethoxy)silane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane,
3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropylmethylmethoxysilane,
N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and
3-chloropropyltrimethoxysilane.
[0118] Examples of the zirconium chelate compounds include
zirconium butoxide, zirconium ethylacetoacetate, zirconium
triethanolamine, acetylacetonate zirconium butoxide,
ethylacetoacetate zirconium butoxide, zirconium acetate, zirconium
oxalate, zirconium lactate, zirconium phosphonate, zirconium
octanoate, zirconium naphthenate, zirconium laurate, zirconium
stearate, zirconium isostearate, methacrylate zirconium butoxide,
stearate zirconium butoxide, and isostearate zirconium
butoxide.
[0119] Examples of the titanium chelate compounds include
tetraisopropyl titanate, tetranormalbutyl titanate, butyl titanate
dimer, tetra(2-ethylhexyl) titanate, titanium acetyl acetonate,
polytitaniumacetyl acetonate, titanium octylene glycolate, titanium
lactate ammonium salt, titanium lactate, titanium lactate ethyl
ester, titanium triethanol aminate, and polyhydroxy titanium
stearate.
[0120] Examples of the aluminum chelate compounds include aluminum
isopropylate, monobutoxy aluminum diisopropylate, aluminum
butylate, diethylacetoacetate aluminum diisopropylate, and aluminum
tris(ethylacetoacetate).
[0121] These additives may be used alone, or as a mixture or a
polycondensate of plural compounds.
[0122] The Vickers hardness of the undercoat layer is preferably 35
or more.
[0123] The surface roughness (ten point height of irregularities)
of the undercoat layer is adjusted in the range of from (1/4)
n.lamda. to (1/2).lamda., in which X represents the wavelength of
the laser for exposure and n represents a refractive index of the
upper layer, in order to prevent a moire image.
[0124] Resin particles and the like may be added in the undercoat
layer in order to adjust the surface roughness. Examples of the
resin particles include silicone resin particles and crosslinked
polymethyl methacrylate resin particles. In addition, the surface
of the undercoat layer may be polished in order to adjust the
surface roughness. Examples of the polishing method include buffing
grinding, a sandblasting treatment, wet honing, and a grinding
treatment.
[0125] The formation of the undercoat layer is not particularly
limited, and well-known forming methods are used. However, the
formation of the undercoat layer is carried out by, for example,
forming a coating film by a coating liquid for forming an undercoat
layer, which is obtained by adding the components above to a
solvent, and drying the coating film, followed by heating, as
desired.
[0126] Examples of the solvent for forming the coating liquid for
forming an undercoat layer include known organic solvents, such as
alcohol solvents, aromatic hydrocarbon solvents, hydrocarbon halide
solvents, ketone solvents, ketone alcohol solvents, ether solvents,
and ester solvents.
[0127] Specific examples of these solvents include ordinary organic
solvents such as methanol, ethanol, n-propanol, iso-propanol,
n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve,
acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl
acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene
chloride, chloroform, chlorobenzene, and toluene.
[0128] Examples of a method for dispersing inorganic particles in
preparing the coating liquid for forming an undercoat layer include
known methods such as methods using a roll mill, a ball mill, a
vibration ball mill, an attritor, a sand mill, a colloid mill, a
paint shaker, and the like.
[0129] Examples of a method for coating the coating liquid for
forming an undercoat layer onto a conductive substrate include
ordinary methods such as a blade coating method, a wire bar coating
method, a spray coating method, a dip coating method, a bead
coating method, an air knife coating method, and a curtain coating
method.
[0130] The film thickness of the undercoat layer is set to a range
of, for example, preferably 15 .mu.m or more, and more preferably
from 20 .mu.m to 50 .mu.m.
[0131] Intermediate Layer
[0132] Although not shown in the figures, an intermediate layer may
be provided between the undercoat layer and the photosensitive
layer.
[0133] The intermediate layer is, for example, a layer including a
resin. Examples of the resin used in the intermediate layer include
polymeric compounds such as acetal resins (for example,
polyvinylbutyral), polyvinyl alcohol resins, polyvinyl acetal
resins, casein resins, polyamide resins, cellulose resins,
gelatins, polyurethane resins, polyester resins, methacrylic
resins, acrylic resins, polyvinyl chloride resins, polyvinyl
acetate resins, vinyl chloride-vinyl acetate-maleic anhydride
resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde
resins, and melamine resins.
[0134] The intermediate layer may be a layer including an organic
metal compound. Examples of the organic metal compound used in the
intermediate layer include organic metal compounds containing a
metal atom such as zirconium, titanium, aluminum, manganese, and
silicon.
[0135] These compounds used in the intermediate layer may be used
alone or as a mixture or a polycondensate of plural compounds.
[0136] Among these, the intermediate layer is preferably a layer
including an organometallic compound containing a zirconium atom or
a silicon atom.
[0137] The formation of the intermediate layer is not particularly
limited, and well-known forming methods are used. However, the
formation of the intermediate layer is carried out, for example, by
forming a coating film by a coating liquid for forming an
intermediate layer, which is obtained by adding the components
above to a solvent, and drying the coating film, followed by
heating, as desired.
[0138] As a coating method for forming an intermediate layer,
ordinary methods such as a dip coating method, an extrusion coating
method, a wire bar coating method, a spray coating method, a blade
coating method, a knife coating method, and a curtain coating
method are used.
[0139] The film thickness of the intermediate layer is set to, for
example, preferably a range of 0.1 .mu.m to 3 .mu.m. Further, the
intermediate layer may be used as an undercoat layer.
[0140] Single Layer Type Photosensitive Layer
[0141] The single layer type photosensitive layer may include a
binder resin, a charge generating material, a hole transport
material, and an electron transport material, and other additives,
as desired.
[0142] Binder Resin
[0143] The binder resin is not particularly limited, but examples
thereof include polycarbonate resins, polyester resins, polyarylate
resins, methacrylic resins, acrylic resins, polyvinyl chloride
resins, polyvinylidene chloride resins, polystyrene resins,
polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene
chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate
copolymers, vinyl chloride-vinyl acetate-maleic anhydride
copolymers, silicone resins, silicone-alkyd resins,
phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinyl
carbazole, and polysilane. These binder resins may be used alone or
as a mixture of two or more kinds thereof.
[0144] Among these binder resins, from the viewpoint of prevention
of segregation of electron transport materials, particularly,
polycarbonate resins and polyarylate resins are preferable.
[0145] Further, from the viewpoint of film-forming property of a
photosensitive layer, as the binder resin, for example,
polycarbonate resins having a viscosity average molecular weight of
30000 to 80000 and polyarylate resins having a viscosity average
molecular weight of 30000 to 80000 are preferable.
[0146] Further, the viscosity average molecular weight is measured
as follows. Specifically, 1 g of a resin is dissolved in 100
cm.sup.3 of methylene chloride, and the specific viscosity .eta.sp
is measured under the measurement condition of 25.degree. C. using
an Ubbellohde's viscometer. Further, an intrinsic viscosity (.eta.)
(cm.sup.3/g) is determined from a relationship equation of
.eta.sp/c=(.eta.)+0.45(.eta.).sup.2c (in which c is a concentration
(g/cm.sup.3)). Further, a viscosity average molecular weight My is
determined from an equation given by H. Schnell,
(.eta.)=1.23.times.10.sup.-4 Mv0.83. As such, for measurement of
the viscosity average molecular weight, for example, a one-point
measurement method is used.
[0147] The content of the binder resin based on the total solid
content of the photosensitive layer is, for example, from 35% by
weight to 60% by weight, and preferably from 40% by weight to 55%
by weight.
[0148] Charge Generating Material
[0149] Examples of the charge generating material include azo
pigments such as bisazo and trisazo pigments; condensed aromatic
pigments such as dibromoanthanthrone pigments; perylene pigments;
pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxides; and
trigonal selenium.
[0150] Among these, in order to correspond to laser exposure in the
near-infrared region, it is preferable to use metal phthalocyanine
pigments or metal-free phthalocyanine pigments as the charge
generating material, and specifically, hydroxygallium
phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, and the
like; chlorogallium phthalocyanine disclosed in JP-A-5-98181 and
the like; dichlorotin phthalocyanine disclosed in JP-A-5-140472,
JP-A-5-140473, and the like; and titanyl phthalocyanine disclosed
in JP-A-4-189873 and the like are more preferable.
[0151] On the other hand, in order to correspond to laser exposure
in the near-ultraviolet region, as the charge generating material,
condensed aromatic pigments such as dibromoanthanthrone; thioindigo
pigments; porphyrazine compounds; zinc oxides; trigonal selenium;
bisazo pigments disclosed in JP-A-2004-78147 and JP-A-2005-181992;
and the like are preferable.
[0152] That is, as the charge generating material, an inorganic
pigment is preferable to correspond to a case where a light source
having an exposure wavelength of from 380 nm to 500 nm is used,
and, a metal phthalocyanine pigment or a metal-free phthalocyanine
pigment is preferable to correspond to a case where a light source
having an exposure wavelength of from 700 nm to 800 nm is used.
[0153] In the exemplary embodiment, as the charge generating
material, at least one selected from a hydroxygallium
phthalocyanine pigment and a chlorogallium phthalocyanine pigment
is preferably used.
[0154] As the charge generating material, these pigments may be
used alone or in combination thereto, as desired. Further, as the
charge generating material, a hydroxygallium phthalocyanine pigment
is preferable from the viewpoints of a high sensitivity of a
photoreceptor and prevention of dot defects of an image.
[0155] The hydroxygallium phthalocyanine pigment is not
particularly limited, but a V-type hydroxygallium phthalocyanine
pigment is preferable.
[0156] Particularly, as the hydroxygallium phthalocyanine pigment,
for example, a hydroxygallium phthalocyanine pigment having a
maximum peak wavelength in the range of from 810 nm to 839 nm in a
spectral absorption spectrum in a wavelength region of from 600 nm
to 900 nm is preferable from the viewpoint that it imparts more
excellent dispersibility. When the hydroxygallium phthalocyanine
pigment is used as a material for an electrophotographic
photoreceptor, excellent dispersibility, sufficient sensitivity,
chargeability, and characteristics of dark attenuation are easily
obtained.
[0157] Further, the hydroxygallium phthalocyanine pigment having a
maximum peak wavelength in the range from 810 nm to 839 nm
preferably has an average particle diameter in a specific range and
a BET specific surface area in a specific range. On the other hand,
the average particle diameter is preferably 0.20 .mu.m or less, and
more preferably from 0.01 .mu.m to 0.15 .mu.m. On the other hand,
the BET specific surface area is preferably 45 m.sup.2/g or more,
more preferably 50 m.sup.2/g or more, and particularly preferably
from 55 m.sup.2/g to 120 m.sup.2/g. An average particle diameter is
a volume average particle diameter (d50 average particle diameter)
and a value measured by a laser diffraction scattering particle
size distribution analyzer LA-700 (manufactured by Horiba Ltd.).
Further, the BET specific surface area is a value measured by a
nitrogen substitution method using a BET specific surface area
analyzer (FLOWSORB 112300, manufactured by Shimadzu
Corporation).
[0158] Here, in the case where the average particle diameter is
more than 0.20 .mu.m or the specific surface area value is less
than 45 m.sup.2/g, the pigment particles are coarsened or
aggregates of pigment particles are formed. Further, the
characteristics such as dispersibility, sensitivity, chargeability,
and dark attenuation characteristics tend to be deteriorated to
result in image defect in some cases.
[0159] A maximum particle diameter (a maximum value of a primary
particle diameter) of the hydroxygallium phthalocyanine pigment is
preferably 1.2 .mu.m or less, more preferably 1.0 .mu.m or less,
and still more preferably 0.3 .mu.m or less. When the maximum
particle diameter exceeds the above range, black spots tend to be
formed.
[0160] From the viewpoint of preventing the density unevenness
caused by exposing a photoreceptor to a fluorescent lamp or the
like from occurring, the hydroxygallium phthalocyanine pigment
preferably has an average particle diameter of 0.2 .mu.m or less,
the maximum particle diameter of 1.2 .mu.m or less and the specific
surface area of 45 m.sup.2/g or more.
[0161] The hydroxygallium phthalocyanine pigment is preferably a V
type one which has diffraction peaks at at least 7.3.degree.,
16.0.degree., 24.9.degree., and 28.0.degree. by a Bragg angle
(20.+-.0.2.degree.) in an X-ray diffraction spectrum obtained using
CuK.alpha. characteristic X-ray.
[0162] On the other hand, the chlorogallium phthalocyanine pigment
is not particularly limited, but preferably has diffraction peaks
at 7.4.degree., 16.6.degree., 25.5.degree., and 28.3.degree. by a
Bragg angle (2.theta..+-.0.20) in an X-ray diffraction spectrum
obtained using CuK.alpha. characteristic X-ray, whereby excellent
sensitivity for an electrophotographic photoreceptor material is
obtained.
[0163] Suitable maximum peak wavelength of the spectral absorption
spectrum, the average particle diameter, the maximum particle
diameter, and the specific surface area value of the chlorogallium
phthalocyanine pigment are the same as those of the hydroxygallium
phthalocyanine pigment.
[0164] The content of the charge generating material based on the
total solid content of the photosensitive layer is preferably from
1% by weight to 5% by weight, and more preferably from 1.2% by
weight to 4.5% by weight.
[0165] Hole Transport Material
[0166] Examples of the hole transport material include triarylamine
compounds, benzidine compounds, arylalkane compounds,
aryl-substituted ethylene compounds, stilbene compounds, anthracene
compounds, and hydrazone compounds. These charge transport
materials may be used alone or in combination of two or more kinds
thereof, but are not limited thereto.
[0167] The hole transport material is preferably a compound
represented by the following formula (B-1), a compound represented
by the following formula (B-2), and a compound represented by the
following formula (B-3) from the viewpoint of charge mobility.
##STR00011##
[0168] In the formula (B-1), R.sup.B1 represents a hydrogen atom or
a methyl group. n11 represents 1 or 2. Ar.sup.B1 and Ar.sup.B2 each
independently represent a substituted or unsubstituted aryl group,
--C.sub.6H.sub.4--C(R.sup.B3).dbd.C(R.sup.B4)(R.sup.B5), or
--C.sub.6H.sub.4--CH.dbd.CH--CH.dbd.C(R.sup.B6)(R.sup.B7), and
R.sup.B3 to R.sup.B7 each independently represent a hydrogen atom,
a substituted or unsubstituted alkyl group, or a substituted or
unsubstituted aryl group. The substituent represents a halogen
atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group
having 1 to 5 carbon atoms, or a substituted amino group
substituted with an alkyl group having 1 to 3 carbon atoms.
##STR00012##
[0169] In the formula (B-2), R.sup.B8 and R.sup.B8' may be the same
as or different from each other and each independently represent a
hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon
atoms, or an alkoxy group having 1 to 5 carbon atoms. R.sup.B9,
R.sup.B9', R.sup.B10', and R.sup.Bl0' may be the same as or
different from each other and each independently represent a
halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy
group having 1 to 5 carbon atoms, a substituted amino group
substituted with an alkyl group having 1 or 2 carbon atoms, a
substituted or unsubstituted aryl group,
--C(R.sup.B11).dbd.C(R.sup.B12) (R.sup.B13), or
--CH.dbd.CH--CH.dbd.C(R.sup.B14) (R.sup.B15), and R.sup.B1 to
R.sup.B15 each independently represent a hydrogen atom, a
substituted or unsubstituted alkyl group, or a substituted or
unsubstituted aryl group. m12, m13, n12, and n13 each independently
represent an integer of 0 to 2.
##STR00013##
[0170] In the formula (B-3), R.sup.B16 and R.sup.B16' may be the
same as or different from each other and each independently
represent a hydrogen atom, a halogen atom, an alkyl group having 1
to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
R.sup.B17, R.sup.B17', R.sup.B18, and R.sup.B18' may be the same as
or different from each other and each independently represent a
halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy
group having 1 to 5 carbon atoms, a substituted amino group
substituted with an alkyl group having 1 or 2 carbon atoms, a
substituted or unsubstituted aryl group,
--C(R.sup.B19).dbd.C(R.sup.B20) (R.sup.B21), or
--CH.dbd.CH--CH.dbd.C(R.sup.B22) (R.sup.B23), and R.sup.B19 to
R.sup.B23 each independently represent a hydrogen atom, a
substituted or unsubstituted alkyl group, or a substituted or
unsubstituted aryl group. m14, m15, n14, and n15 each independently
represent an integer of 0 to 2.
[0171] Here, among the compound represented by the formula (B-1),
the compound represented by the formula (B-2), and the compound
represented by the formula (B-3), the compound represented by the
formula (B-1) having
"--C.sub.6H.sub.4--CH.dbd.CH--CH.dbd.C(R.sup.B6) (R.sup.B7)" and
the compound represented by the formula (B-2) having
"--CH.dbd.CH--CH.dbd.C(R.sup.B14) (R.sup.B15)" are preferable.
[0172] Specific examples of the compound represented by the formula
(B-1), the compound represented by the formula (B-2), and the
compound represented by the formula (B-3) include the following
compounds.
##STR00014## ##STR00015##
[0173] The content of the hole transport material based on the
total solid content of the photosensitive layer is preferably from
10% by weight to 40% by weight, and more preferably from 20% by
weight to 35% by weight. Further, the content of the hole transport
material is the content of the entire hole transport materials in
the case of using a combination of plural kinds of hole transport
materials.
[0174] Electron Transport Material
[0175] As the electron transport material, at least an electron
transport material represented by the formula (1) is used, but may
be used alone, or may be used in combination of other electron
transport materials, as desired, within a range not adversely
affecting the invention.
[0176] The content of the electron transport material represented
by the formula (1) based on the total solid content of the
photosensitive layer is preferably from 1% by weight to 30% by
weight, and more preferably from 5% by weight to 20% by weight. By
setting the content of the electron transport material represented
by the formula (1) based on the total solid content of the
photoreceptor to the above range, as compared with a case where the
content of the electron transport material represented by the
formula (1) is less, the electrical characteristics of the
photoreceptor becomes better, whereas as compared with a case where
the content of the electron transport material represented by the
formula (1) is more than the range, fog or color dots are hardly
formed on an image thus formed.
[0177] Further, in the case where other electron transport
materials are used as the electron transport material, it is
preferable to use other electron transport materials in the amount
of 50% by weight or less based on the total amount of the electron
transport material.
[0178] Examples of the other electron transport materials include
electron transport compounds, such as fluorenone derivatives other
than the electron transport material represented by the formula
(1); quinone compounds such as p-benzoquinone, chloranil, bromanil,
and anthraquinone; tetracyanoquinodimethane compounds; fluorenone
compounds such as 2,4,7-trinitrofluorenone; xanthone compounds;
benzophenone compounds; cyanovinyl compounds; and ethylene
compounds. These other charge transport materials may be used alone
or in combination of two or more kinds thereof, but are not limited
thereto.
[0179] Specific examples of the other electron transport material
include the following compounds.
##STR00016##
[0180] The ratio of the hole transport material to the electron
transport material is preferably from 50/50 to 90/10, and more
preferably from 60/40 to 80/20, in terms of a weight ratio (hole
transport material/electron transport material).
[0181] In addition, in the case of using other electron transport
materials in combination, the "electron transport materials" in
this ratio is a sum of the combination of the materials.
[0182] Other Additives
[0183] The single layer type photosensitive layer may include other
known additives such as a surfactant, an antioxidant, a light
stabilizer, and a heat stabilizer. Further, in the case where the
single layer type photosensitive layer is a surface layer, it may
include fluorine resin particles, silicone oils, or the like.
[0184] Formation of Single Layer Type Photosensitive layer
[0185] The single layer type photosensitive layer is formed by
using a coating liquid for forming a photosensitive layer, which is
prepared by adding the above components in a solvent.
[0186] Examples of the solvent include ordinary organic solvents,
such as aromatic hydrocarbons such as benzene, toluene, xylene, and
chlorobenzene; ketones such as acetone and 2-butanone; aliphatic
hydrocarbon halides such as methylene chloride, chloroform, and
ethylene chloride; and cyclic or linear ethers such as
tetrahydrofuran and ethyl ether. These solvents may be used alone
or in combination of two or more kinds thereof.
[0187] For a method for dispersing particles (for example, charge
generating materials) in the coating liquid for forming a
photosensitive layer, for example, a media dispersing machine such
as a ball mill, a vibrating ball mill, an attritor, a sand mill,
and a horizontal sand mill, or a medialess dispersing machine such
as a stirrer, an ultrasonic dispersing machine, a roll mill, and a
high-pressure homogenizer is used. Examples of the high-pressure
homogenizer include a collision system in which the particles are
dispersed by causing the dispersion to collide against liquid or
against walls under a high pressure, and a penetration system in
which the particles are dispersed by causing the dispersion to
penetrate through a fine flow path under a high pressure.
[0188] Examples of a method for coating the coating liquid for
forming a photosensitive layer onto the undercoat layer include a
dip coating method, an extrusion coating method, a wire bar coating
method, a spray coating method, a blade coating method, a knife
coating method, and a curtain coating method.
[0189] The film thickness of the single layer type photosensitive
layer is set to a range of preferably from 5 .mu.m to 60 m, more
preferably from 5 .mu.m to 50 .mu.m, and still more preferably from
10 .mu.m to 40 .mu.m.
[0190] Image Forming Apparatus (and Process Cartridge)
[0191] The image forming apparatus according to the present
exemplary embodiment is provided with an electrophotographic
photoreceptor, a charging unit that charges the surface of the
electrophotographic photoreceptor, an electrostatic latent image
forming unit that forms an electrostatic latent image on the
surface of a charged electrophotographic photoreceptor, a
developing unit that develops the electrostatic latent image formed
on the surface of the electrophotographic photoreceptor by a
developer including a toner to form a toner image, and a transfer
unit that transfers the toner image onto a surface of a recording
medium. Further, the electrophotographic photoreceptor according to
the present exemplary embodiment is applied as the
electrophotographic photoreceptor.
[0192] As the image forming apparatus according to the present
exemplary embodiment, known image forming apparatuses provided with
a device including a fixing unit that fixes a toner image
transferred to the surface of a recording medium; a direct transfer
type device that directly transfers the toner image formed on the
surface of the electrophotographic photoreceptor to a recording
medium; an intermediate transfer type device that primarily
transfers the toner image formed on the surface of the
electrophotographic photoreceptor on the surface of the
intermediate transfer member, and secondarily transfers the toner
image transferred to the surface of an intermediate transfer member
to the surface of the recording medium; a device provided with a
cleaning unit that cleans the surface of the electrophotographic
photoreceptor before charging, after the transfer of the toner
image; a device provided with a charge erasing unit that erases
charges by irradiating erasing light onto the surface of an image
holing member before charging, after the transfer of the toner
image; a device provided with an electrophotographic photoreceptor
heating unit that increases the temperature of the
electrophotographic photoreceptor to reduce the relative
temperature; and the like are applied.
[0193] In the case of the intermediate transfer type device case,
for the transfer unit, for example, a configuration in which an
intermediate transfer member to the surface of which the toner
image is transferred, a primary transfer unit that primarily
transfers a toner image formed on the surface of an image holding
member to the surface of the intermediate transfer member, and a
secondary transfer unit that secondarily transfers the toner image
transferred to the surface of the intermediate transfer member on
the surface of the recording medium is applied.
[0194] The image forming apparatus according to the present
exemplary embodiment is any one of a dry development type image
forming apparatus and a wet development type (development type
using a liquid developer) image forming apparatus.
[0195] Furthermore, in the image forming apparatus according to the
present exemplary embodiment, for example, a part provided with the
electrophotographic photoreceptor may be a cartridge structure
(process cartridge) that is detachable from an image forming
apparatus. As the process cartridge, for example, a process
cartridge including the electrophotographic photoreceptor according
to the present exemplary embodiment is suitably used. Further, the
process cartridge may include, in addition to the
electrophotographic photoreceptor, for example, at least one
selected from the group consisting of a charging means, an
electrostatic latent image forming unit, a developing unit, and a
transfer unit.
[0196] Hereinafter, one example of the image forming apparatuses
according to the present exemplary embodiment is shown, but the
present invention is not limited thereto. Further, the main parts
shown in the figures are described, and explanation of the others
will be omitted.
[0197] FIG. 2 is a schematic structural view showing an example of
the image forming apparatus according to the present exemplary
embodiment.
[0198] The image forming apparatus 100 according to the present
exemplary embodiment is provided with a process cartridge 300
provided with an electrophotographic photoreceptor 7 as shown in
FIG. 2, an exposure device 9 (one example of the electrostatic
latent image forming unit), a transfer device 40 (primary transfer
device), and an intermediate transfer member 50. Further, in the
image forming apparatus 100, the exposure device 9 is arranged at a
position where the exposure device 9 may radiate light onto the
electrophotographic photoreceptor 7 through an opening in the
process cartridge 300, and the transfer device 40 is arranged at a
position opposite to the electrophotographic photoreceptor 7 by the
intermediary of the intermediate transfer member 50. The
intermediate transfer member 50 is arranged to contact partially
the electrophotographic photoreceptor 7. Further, although not
shown in the figure, the apparatus also includes a secondary
transfer device that transfers a toner image transferred onto the
intermediate transfer member 50 to a recording medium (for example,
paper). Further, the intermediate transfer member 50, the transfer
device 40 (primary transfer device), and the secondary transfer
device (not shown) correspond to an example of the transfer
unit.
[0199] The process cartridge 300 in FIG. 2 supports, in a housing,
the electrophotographic photoreceptor 7, a charging device 8 (one
example of the charging unit), a developing device 11 (one example
of the developing unit), and a cleaning device 13 (one example of
the cleaning unit) integrally. The cleaning device 13 has a
cleaning blade (one example of the cleaning member) 131, and the
cleaning blade 131 is arranged so as to be in contact with the
surface of the electrophotographic photoreceptor 7. Further, the
cleaning member is not an embodiment of the cleaning blade 131, may
be a conductive or insulating fibrous member, and may be used alone
or in combination with the cleaning blade 131.
[0200] Furthermore, FIG. 2 shows an example that includes fibrous
member 132 (roll shape) that supplies a lubricant 14 to the surface
of the electrophotographic photoreceptor 7 as the image forming
apparatus, and a fibrous member 133 (flat brush shape) that assists
in cleaning, but these members are disposed, as desired.
[0201] Hereinafter, the respective configurations of the image
forming apparatus according to the present exemplary embodiment
will be described.
[0202] Charging Device
[0203] As the charging device 8, for example, a contact type
charging device using a conductive or semiconductive charging roll,
a charging brush, a charging film, a charging rubber blade, a
charging tube, or the like is used. Further, per se known charging
devices, such as a non-contact type roller charging device, and a
scorotron charging device and a corotron charging device, each
using corona discharge, and the like are also used.
[0204] Exposure Device
[0205] The exposure device 9 may be an optical instrument for
exposure of the surface of the electrophotographic photoreceptor 7,
to rays such as a semiconductor laser ray, an LED ray, and a liquid
crystal shutter ray according to an image data. The wavelength of
the light source may be a wavelength in the range from the spectral
sensitivity wavelengths of the electrophotographic photoreceptor.
As the wavelengths of semiconductor lasers, near infrared
wavelengths that are oscillation wavelengths near 780 nm are
predominant. However, the wavelength of the laser ray to be used is
not limited to such a wavelength, and a laser having an oscillation
wavelength of 600 nm range, or a laser having any oscillation
wavelength in the range from 400 nm to 450 nm as a blue laser may
be used. In order to form a color image, it is also effective to
use a planar light emission type laser light source capable of
attaining a multi-beam output.
[0206] Developing Device
[0207] As the developing device 11, for example, a common
developing device, in which a developer is contacted or not
contacted for forming an image, may be used. Such a developing
device 11 is not particularly limited as long as it has the
above-described functions, and may be appropriately selected
according to the intended use. Examples thereof include a known
developing device in which the single-component or two-component
developer is adhered to the electrophotographic photoreceptor 7
using a brush or a roller. Among these, the developing device using
developing roller retaining developer on the surface thereof is
preferable.
[0208] The developer used in the developing device 11 may be a
single-component developer formed of a toner alone or a
two-component developer formed of a toner and a carrier. Further,
the developer may be magnetic or non-magnetic. As the developer,
known ones may be applied.
[0209] Cleaning Device
[0210] As the cleaning device 13, a cleaning blade type device
provided with the cleaning blade 131 is used.
[0211] Further, in addition to the cleaning blade type, a fur brush
cleaning type and a type of performing developing and cleaning at
once may also be employed.
[0212] Transfer Device
[0213] Examples of the transfer device 40 include per se known
transfer charging devices, such as a contact type transfer charging
device using a belt, a roller, a film, a rubber blade, or the like,
a scorotron transfer charging device utilizing corona discharge,
and a corotron transfer charging device utilizing corona
discharge.
[0214] Intermediate Transfer Member
[0215] As the intermediate transfer member 50, a form of a belt
(intermediate transfer belt) composed of polyimide, polyamideimide,
polycarbonate, polyarylate, polyester, rubber, or the like, which
is imparted with the semiconductivity, is used. In addition, the
intermediate transfer member may also take the form of a drum, in
addition to the form of a belt.
[0216] FIG. 3 is a schematic structural view showing another
example of the image forming apparatus according to the present
exemplary embodiment.
[0217] The image forming apparatus 120 shown in FIG. 3 is a tandem
type full color image forming apparatus equipped with four process
cartridges 300. In the image forming apparatus 120, four process
cartridges 300 are disposed parallel with each other on the
intermediate transfer member 50, and one electrophotographic
photoreceptor may be used for one color.
[0218] Further, the image forming apparatus 120 has the same
configuration as the image forming apparatus 100, except that it is
a tandem type.
[0219] Further, the image forming apparatus 100 according to the
present exemplary embodiment is not limited to the configuration,
and for example, it is in the periphery of the electrophotographic
photoreceptor 7. Further, it may be configured to provide a first
erasing device for making the erasing with a cleaning brush easier
by matching the polarity of the residual toner on the downstream
side in the rotating direction of the electrophotographic
photoreceptor 7 from the transfer device 40 and on the upstream
side in the rotating direction of the electrophotographic
photoreceptor from the cleaning device 13, or to provide a second
erasing device by erasing the charge of the surface of the
electrophotographic photoreceptor 7 on the downstream side in the
rotating direction of the electrophotographic photoreceptor from
the cleaning device 13 and on the upstream side in the rotating
direction of the electrophotographic photoreceptor from the
charging device 8.
[0220] Furthermore, the image forming apparatus 100 according to
the present exemplary embodiment is not limited to the
configurations above, and for example, an image forming apparatus
having a well-known configuration, in a direct transfer mode, in
which a toner image formed in an electrophotographic photoreceptor
7 is directly transferred onto a recording medium, may be
employed.
EXAMPLES
[0221] Hereinafter, the present invention will be described in more
detail with reference to Examples and Comparative Examples, but the
invention is not limited to Examples below in any way.
Synthesis of Electron Transport Material
Synthesis Example 1
Synthesis of Exemplary Compound (1-36)
[0222] To 25 g of 9-fluorenone-4-carboxylic acid is added 150 ml of
thionyl chloride, followed by heating and stirring at 80.degree. C.
for 6 hours. After cooling to room temperature (25.degree. C.), 150
ml of n-hexane is added thereto and the precipitated crystals are
filtered to obtain 23 g (yield of 86%) of 9-fluorenone-4-carboxylic
acid chloride. Next, to a solution obtained by mixing 15.5 g of
2,4-di-t-pentylphenol, 150 ml of toluene, and 6.7 g of
triethylamine is added 14.5 g of 9-fluorenone-4-carboxylic acid
chloride obtained above, followed by stirring at room temperature
(25.degree. C.) for 48 hours. The reactant is purified by silica
gel chromatography to obtain 22 g of an exemplary compound (1-36)
which is a desired product. The melting point of the obtained
exemplary compound (1-36) is from 164.degree. C. to 167.degree. C.
Further, the IR spectrum (infrared absorption spectrum) of the
obtained exemplary compound (1-36) is shown in FIG. 4.
Synthesis Example 2
Synthesis of Exemplary Compound (1-37)
[0223] By performing the synthesis in the same manner as in
Synthesis Example 1 except that 15.5 g of 2,4-di-t-pentylphenol of
Synthesis Example 1 is changed to 21.8 g of
2,4-bis(.alpha.,.alpha.-dimethylbenzyl)phenol, 22 g of an exemplary
compound (1-37) which is a desired product is obtained. The melting
point of the obtained exemplary compound (1-37) is from 174.degree.
C. to 175.degree. C. Further, the IR spectrum (infrared absorption
spectrum) of the obtained exemplary compound (1-37) is shown in
FIG. 5.
Synthesis Example 3
Synthesis of Exemplary Compound (1-11)
[0224] 9.9 g of the exemplary compound (1-36) obtained in Synthesis
Example 1 is dissolved in 150 ml of ethyl acetate under warming,
and 2.3 g of malononitrile and 0.2 g of piperidine are added
thereto, followed by stirring at 50.degree. C. for 5 hours. The
precipitated crystals are filtered and purified by silica gel
chromatography to obtain 9.0 g of an exemplary compound (1-11)
which is a desired product. The melting point of the obtained
exemplary compound (1-11) is from 198.degree. C. to 200.degree. C.
Further, the IR spectrum (infrared absorption spectrum) of the
obtained exemplary compound (1-11) is shown in FIG. 6.
Synthesis Example 4
Synthesis of Exemplary Compound (1-12)
[0225] 8.8 g of the exemplary compound (1-37) obtained in Synthesis
Example 2 is dissolved in 150 ml of ethyl acetate under warming,
and 2.3 g of malononitrile and 0.2 g of piperidine are added
thereto, followed by stirring at 50.degree. C. for 5 hours. The
precipitated crystals are filtered and purified by silica gel
chromatography to obtain 9.2 g of an exemplary compound (1-12)
which is a desired product. The melting point of the obtained
exemplary compound (1-12) is from 227.degree. C. to 230.degree. C.
Further, the IR spectrum (infrared absorption spectrum) of the
obtained exemplary compound (1-12) is shown in FIG. 7.
Comparative Synthesis Example 1
Synthesis of Comparative Compound 1 Shown Below
[0226] By performing the synthesis in the same manner as in
Synthesis Example 1 except that 2,4-di-t-pentylphenol of Synthesis
Example 1 is changed to phenol, a comparative compound 1 is
obtained. The melting point of the comparative compound 1 is from
198.degree. C. to 199.degree. C. Further, the IR spectrum (infrared
absorption spectrum) of the obtained comparative compound 1 is
shown in FIG. 8.
##STR00017##
Comparative Synthesis Examples 2 to 5
[0227] Synthesis of Comparative Compounds 2 to 5 Shown Below By
performing the synthesis in the same manner as in Comparative
Synthesis Example 1 except that phenol of Comparative Synthesis
Example 1 is changed to each corresponding compound, comparative
compounds 2 to 5 are obtained.
##STR00018##
Preparation of Photoreceptor
Example 1
Formation of Undercoat Layer
[0228] 100 parts by weight of zinc oxide (average particle diameter
of 70 nm: manufactured by Tayca Corporation: specific surface area
value of 15 m.sup.2/g) is stirred and mixed with 500 parts by
weight of tetrahydrofuran, and 1.2 parts by weight of a silane
coupling agent (KBE502: manufactured by Shin-Etsu Chemical Co.,
Ltd.) is added thereto, followed by stirring for 2 hours.
Thereafter, tetrahydrofuran is evaporated by distillation under
reduced pressure, and baking is performed at 120.degree. C. for 3
hours to obtain zinc oxide surface-treated with a silane coupling
agent.
[0229] 110 parts by weight of the obtained zinc oxide
surface-treated with a silane coupling agent is stirred and mixed
with 500 parts by weight of tetrahydrofuran, and a solution formed
by dissolving 0.7 parts by weight of alizarin in 50 parts by weight
of tetrahydrofuran is added thereto, followed by stirring at
50.degree. C. for 4 hours. Subsequently, zinc oxide to which
alizarin is attached is separated by filtration under a reduced
pressure and dried under reduced pressure at 65.degree. C. to
obtain alizarin-attached zinc oxide.
[0230] 38 parts by weight of a solution formed by dissolving 60
parts by weight of alizarin-attached zinc oxide, 13.5 parts by
weight of a curing agent (blocked isocyanate, Sumidur 3175,
manufactured by Sumitomo-Bayer Urethane Co., Ltd.) and 15 parts by
weight of a butyral resin (S-Lec BM-1, manufactured by Sekisui
Chemical Co., Ltd.) in 85 parts by weight of methyl ethyl ketone is
mixed with 30 parts by weight of methyl ethyl ketone. The mixture
is dispersed using a sand mill with glass beads having a diameter
of 1 mm.phi. for 2 hours and 30 minutes to obtain a dispersion.
[0231] 0.005 part by weight of dioctyl tin dilaurate as a catalyst
and 40 parts by weight of silicone resin particles (Tospearl 145,
manufactured by GE Toshiba Silicone Co., Ltd.) are added to the
obtained dispersion to obtain a coating liquid for forming an
undercoat layer.
[0232] The obtained coating liquid is coated on an aluminum
substrate having a diameter of 30 mm, a length of 340 mm, and a
thickness of 1 mm by a dip coating method, and dried to cure at
170.degree. C. for 35 minutes, thereby obtaining an undercoat layer
having a thickness of 16 m.
[0233] Formation of Photosensitive layer
[0234] A mixture including 2 parts by weight of a hydroxygallium
phthalocyanine pigment shown in Table 1 below as a charge
generating material, 49 parts by weight of a copolymerization type
polycarbonate resin (A) (viscosity average molecular weight of
50000) having the following structure as a binder resin, 200 parts
by weight of tetrahydrofuran as a solvent, and 100 parts by weight
of monochlorobenzene as a solvent is dispersed using a sand mill
with glass beads having a diameter of 1 mm.phi. for 3 hours to
obtain a dispersion.
##STR00019##
[0235] To the obtained dispersion are added 31 parts by weight of a
hole transport material shown in Table 1 below and 15 parts by
weight of an electron transport material shown in Table 1 and 0.001
parts by weight of a silicone oil KP340 (manufactured by Shin-Etsu
Chemical Co., Ltd.), followed by stirring overnight, thereby
obtaining a coating liquid for forming a photosensitive layer.
##STR00020##
[0236] A single layer type photosensitive layer having a film
thickness of 26 .mu.m is formed by coating the obtained coating
liquid for forming a photosensitive layer on the undercoat layer
formed on the aluminum substrate using a dip coating method, and
drying at 140.degree. C. for 1 hour.
[0237] Through the above steps, an electrophotographic
photoreceptor is prepared.
Examples 2 to 10 and Comparative Examples 1 to 5
[0238] In the same manner as in Example 1 except that the presence
or absence of the undercoat layer, the kind of the charge
generating material used in the coating liquid for forming a
photosensitive layer, the kind of the hole transport material, and
the kind of the electron transport material are changed according
to Table 1, each electrophotographic photoreceptor is prepared.
TABLE-US-00002 TABLE 1 Charge Hole Electron Undercoat generating
transport transport Example Photoreceptor layer material material
material Example 1 Photoreceptor 1 Included HOGaPC HT-7 I-11
Example 2 Photoreceptor 2 None HOGaPC HT-7 I-11 Example 3
Photoreceptor 3 Included HOGaPC HT-4 I-12 Example 4 Photoreceptor 4
None HOGaPC HT-4 I-12 Example 5 Photoreceptor 5 None ClGaPC HT-1
I-11 Example 6 Photoreceptor 6 None ClGaPC HT-1 I-12 Example 7
Photoreceptor 7 None ClGaPC HT-7 I-12 Example 8 Photoreceptor 8
None ClGaPC HT-7 I-36 Example 9 Photoreceptor 9 None X type HT-1
I-37 metal-free phthalocyanine Example 10 Photoreceptor None X type
HT-1 I-38 10 metal-free phthalocyanine Comparative Comparative
Included HOGaPC HT-1 Comparative Example 1 photoreceptor 1 compound
1 Comparative Comparative None HOGaPC HT-1 Comparative Example 2
photoreceptor 2 compound 2 Comparative Comparative None HOGaPC HT-4
Comparative Example 3 photoreceptor 3 compound 3 Comparative
Comparative None ClGaPC HT-1 Comparative Example 4 photoreceptor 4
compound 4 Comparative Comparative None X type HT-1 Comparative
Example 5 photoreceptor 5 metal-free compound 5 phthalocyanine
[0239] Further, details on the abbreviations in Table 1 are as
follows.
[0240] Charge Generating Material [0241] HOGaPC: Hydroxygallium
phthalocyanine (V type): V type hydroxygallium phthalocyanine
pigment having diffraction peaks at the positions of at least
7.3.degree., 16.0.degree., 24.9.degree., and 28.0.degree. by a
Bragg angle (20.+-.0.20) in an X-ray diffraction spectrum obtained
using CuK.alpha. characteristic X-ray (the maximum peak wavelength
in a spectral absorption spectrum in a wavelength region of from
600 nm to 900 nm=820 nm, average particle diameter=0.12 .mu.m,
maximum particle diameter=0.2 .mu.m, specific surface area value=60
m.sup.2/g) [0242] ClGaPC: Chlorogallium phthalocyanine:
chlorogallium phthalocyanine pigment having diffraction peaks at
the positions of at least 7.4.degree., 16.6.degree., 25.5.degree.,
and 28.3.degree. by a Bragg angle (2.theta..+-.0.2.degree.) in an
X-ray diffraction spectrum obtained using CuK.alpha. characteristic
X-ray (the maximum peak wavelength in a spectral absorption
spectrum in a wavelength region of from 600 nm to 900 nm=780 nm,
average particle diameter=0.15 .mu.m, maximum particle diameter=0.2
.mu.m, specific surface area value=56 m.sup.2/g) [0243] X type
metal-free phthalocyanine: H.sub.2PC: metal-free phthalocyanine
pigment (phthalocyanine having two hydrogen atoms coordinated at
the center of a phthalocyanine skeleton)
[0244] Hole Transport Material [0245] HT-7: an exemplary compound
(HT-7) of the compound represented by the formula (B-1) [0246]
HT-4: an exemplary compound (HT-4) of the compound represented by
the formula (B-1) [0247] HT-1: an exemplary compound (HT-1) of the
compound represented by the formula (B-2)
[0248] Electron Transport Material [0249] 1-11: an exemplary
compound (1-11) obtained in Synthesis Example 3 [0250] 1-12: an
exemplary compound (1-12) obtained in Synthesis Example 4 [0251]
1-36: an exemplary compound (1-36) obtained in Synthesis Example 1
[0252] 1-37: an exemplary compound (1-37) obtained in Synthesis
Example 2 [0253] Comparative compound 1: Comparative compound 1
obtained in Comparative Synthesis Example 1 [0254] Comparative
compound 2: Comparative compound 2 obtained in Comparative
Synthesis Example 2 [0255] Comparative compound 3: Comparative
compound 3 obtained in Comparative Synthesis Example 3 [0256]
Comparative compound 4: Comparative compound 4 obtained in
Comparative Synthesis Example 4 [0257] Comparative compound 5:
Comparative compound 5 obtained in Comparative Synthesis Example
5
[0258] Evaluation
[0259] The following evaluations on each of the obtained
electrophotographic photoreceptors are carried out, and the results
are shown in Table 2.
[0260] Evaluation on Image Quality for Blur
[0261] Using Brother HL2270DW under an environment of a room
temperature of 28.degree. C. and a humidity of 85%, 5000 sheets of
a 100% black solid image are formed and the presence or absence of
generation of the blur of an image on the 5000.sup.th sheet is
visually observed and evaluated according to the following
criteria.
[0262] A: No generation of blur (blur is not visually observed)
[0263] B: Some blur is visually observed in the transverse portion
of a paper.
[0264] C: White blur is clearly generated
[0265] Evaluation of Charge Maintenance
[0266] Using Brother HL2270DW under an environment of a room
temperature of 28.degree. C. and a humidity of 85%, 20000 A4-sized
sheets of a 100% black solid image are formed and the charge
potentials are measured before and after forming 20000 sheets and
the decrease in the charge potential by image formation is
evaluated according to the following criteria.
[0267] Further, the charge potential is determined by measuring the
potential of the surface of the electrophotographic photoreceptor
before charging and exposing by a device in which a developer unit
inside the HL2270DW is replaced by a potential probe.
[0268] A: The charge potential is decreased by 35 V or less.
[0269] B: The charge potential is decreased by more than 35 V and
50 V or less.
[0270] C: The charge potential is decreased by more than 50 V.
TABLE-US-00003 TABLE 2 Charge potential Evaluation after on charge
Initial printing maintenance Evaluation on charge 20000 (decrease
in Example Photoreceptor blur potential sheets potential) Example 1
Photoreceptor 1 A 600 V 572 V A (-28 V) Example 2 Photoreceptor 2 A
605 V 578 V A (-27 V) Example 3 Photoreceptor 3 A 601 V 576 V A
(-25 V) Example 4 Photoreceptor 4 A 603 V 571 V A (-32 V) Example 5
Photoreceptor 5 A 596 V 561 V A (-35 V) Example 6 Photoreceptor 6 A
600 V 572 V A (-28 V) Example 7 Photoreceptor 7 A 602 V 577 V A
(-25 V) Example 8 Photoreceptor 8 A 599 V 578 V A (-21 V) Example 9
Photoreceptor 9 A 606 V 572 V A (-34 V) Example 10 Photoreceptor 10
A 603 V 570 V A (-33 V) Comparative Comparative C 601 V 543 V C
(-58 V) Example 1 photoreceptor 1 Comparative Comparative C 595 V
541 V C (-54 V) Example 2 photoreceptor 2 Comparative Comparative B
600 V 557 V B (-43 V) Example 3 photoreceptor 3 Comparative
Comparative B 600 V 553 V B (-47 V) Example 4 photoreceptor 4
Comparative Comparative B 604 V 559 V B (-45 V) Example 5
photoreceptor 5
[0271] Furthermore, as a result of evaluating the photoreceptors of
Comparative Examples 1 and 2 as described above, it is found that
slight crystallization is visually observed on the surface and
defects in the form of dragged stripe patterns are found.
[0272] From the results above, it may be seen that in the present
Example, the blur of an image hardly occurs and the charge
maintenance is also good, as compared with Comparative Examples,
and thus, the morphological change of the film is prevented and the
stability is maintained.
[0273] The foregoing description of the exemplary embodiments of
the present invention has been provided for the purposes of
illustration and description. It is not intended to be exhaustive
or to limit the invention to the precise forms disclosed.
Obviously, many modifications and variations will be apparent to
practitioners skilled in the art. The embodiments were chosen and
described in order to best explain the principles of the invention
and its practical applications, thereby enabling others skilled in
the art to understand the invention for various embodiments and
with the various modifications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
defined by the following claims and their equivalents.
* * * * *